Harris Atlas DVL400 Technical Manual page 108

Section 4 Theory of Operation
a. ON_/OFF
This command corresponds to the transmitter operator pushing the "ON" or
"OFF" button, thereby turning the transmitter on or off respectively. This sig-
nal is high for ON and low for OFF. This is driven only by the Main Control-
ler and is a sense only line for the rest of the control boards.
b. /RESTRIKE (reset)
This command is monitored by all of the control boards but is driven only by
the Main Controller board. When the transmitter is already turned ON and the
operator presses the "ON" button again, this line will be pulsed low for a min-
imum of 100ms. This will cause all of the controller boards to reset any faults
and status and try to return to normal operation. This line is a sense only line
for the rest of the control boards.
This command is basically a RESET pulse which will try to turn on any trans-
mitter components which have faulted off due to a critical fault condition. If
they are still faulty, this will be detected and the component will simply be
shut off again. This will not reset or clear the Fault Log.
c. /FLT_OFF
This command is initiated whenever a fault occurs that requires all RF to be
shut off and the PA supplies to be disabled. This is a latching type signal that
requires user input to clear the fault and turn the transmitter back on. This sig-
nal is active low. The Main Controller, PS Monitor, External I/O and RF
Monitor Boards monitor this line and have the ability to activate it if neces-
sary.
d. /RF_MUTE
The /RF_MUTE line shuts down all RF output temporarily until the fault con-
dition is cleared. This is a non-latching signal. The Main Controller, PS Mon-
itor, External I/O and RF Monitor Boards monitor this line and have the
ability to activate it if necessary.
e. /PS_MUTE
The /PS_MUTE line shuts down the output of the 32 Volt PA module sup-
plies temporarily until the fault condition is cleared. This is a non-latching
signal. The Main Controller, PS Monitor, External I/O and RF Monitor
Boards monitor this line and have the ability to activate it if necessary.
f. /AC_LOW
This signal is an early warning of impending loss of control voltage. When
the AC line voltage that powers the LVPS(s) drops below an acceptable
threshold the board will pull this open collector line low. For a single phase
system, the sample from L1 to L2 (A-B) will be monitored. For a three phase
system, phase sample L3-L1 (C-A) will be monitored. The other boards in the
control system will use this indication as an advanced warning to save any
data and prepare for loss of power.
The PS Monitor board is the only control board with the ability to drive this
signal and it will affect the Main Controller, External I/O and RF Monitor
Boards.
4-8
WARNING: Disconnect primary power prior to servicing.
888-2473-001
ATLAS Series™
2/25/03